<!DOCTYPE html>
<style>
html, body {
    margin: 0;
}
section {
    position: absolute;
    width: 100px;
    height: 100px;
    top: 0;
    left: 0;
    background: gold;
}
nav {
    position: absolute;
    width: 200px;
    height: 100px;
    top: 0;
    left: 100px;
    background: blue;
}
</style>
<section></section><nav></nav>

